class Solution {
public:
    int numJewelsInStones(string jewels, string stones) {
        unordered_map<char, int> mmp;
        for (auto e : jewels)
        {
            mmp[e]++;
        }
        int ret = 0;
        for (auto e : stones)
        {
            if (mmp[e] != 0)
                ret++;
        }
        return ret;
    }
};